More and more electronic devices are accommodated in a certain package volume with an increased integration level of electronic devices and miniaturization of electronic products. Both miniaturization of each electronic product and an improved package of electronic devices are required. In a chip package, multiple chips will have a large footprint if being arranged in a plane, and will be difficult to be used in some compact products.
To solve the problem, one skilled person introduces a multi-chip package, in which multiple chips are stacked in a volume and electrically coupled to a substrate by leads. Such a conventional package solves the problem of a large footprint of multiple chips, but the multiple chips in a package are not elaborately arranged and electrically coupled to each other. Actually, electrical connections among the multiple chips are provided by external circuits. Consequently, it is difficult for the conventional multi-chip package to provide electrical connections among the multiple chips in different levels.